Science Translational Medicine, Vitamin C and cancer: a potential CoI and a lack of transparency

The recent Ma et al. Science Translational Medicine article on “High-Dose Parenteral Ascorbate Enhanced Chemosensitivity of Ovarian Cancer and Reduced Toxicity of Chemotherapy” has received a lot of attention recently – for example, the BBC initially reported it as suggesting “Vitamin C keeps cancer at bay”.* However, Jeanne Drisko (one of the corresponding authors) has a potential Conflict of Interest (CoI) which was not noted in the article. Science Translational Medicine (STM) will be correcting what they view as an “oversight” after I e-mailed to let them know about this, but their response has generally been disappointing: they have not been nearly transparent enough in handling this potential CoI’s omission from the published article.

Ma et al. (2014: 10) states that “The authors declare that they have no competing interests.” Drisko, though, is listed as Chairman of the Alliance for Natural Health USA (ANH-USA): a campaigning organisation that describes itself as “dedicated to promoting integrative medicine and sustainable health”.** Intravenous vitamin C is, as the Kansas University press release promoting this article notes, “currently administered intravenously to thousands of patients by practitioners of complementary and alternative medicine”. STM’s Conflict of Interest policy asks that authors declare “all affiliations…or management relationships related to the reported research, including those that could be perceived as potential sources of bias”. When an author has a senior role in an organisation campaigning on issues related to the article, this could reasonably be viewed as a potential source of bias and should therefore be declared.

I don’t know whether this potential Conflict of Interest (CoI) was declared to STM when the article was submitted by the authors or accepted for publication: the journal refused to tell me, arguing that

the specific content of CoI forms is confidential

This is a long way from an open CoI policy! What STM did tell me is that

We have looked into this issue and discovered that the potential conflict of interest you highlighted (which is entirely non-commercial and non-financial) was inadvertently left off due to a misunderstanding. We are now working to correct this accidental oversight.

I am pleased that STM are working to correct this, but this lack of transparency about whether the potential conflict was declared is unfortunate.*** STM also declined to clarify whether their interpretation of the journal’s CoI policy is the same as mine, arguing that

Although I could provide an interpretation of the statement on the website, I don’t see how that would be fair to the authors. The authors do not normally get customized interpretations from journal editors, but instead have to make their own interpretations. You now have exactly as much information as the authors did when working on their forms.

Alongside STM’s disappointing response, it’s rather a shame that it’s left to me to publicise this potential CoI – after the end of most of the media puff around the piece. Given the article’s topic, STM and the journalists covering the story should have realised its potential to have high impact outside of academia – intravenous and oral vitamin C are both heavily marketed to cancer patients and other vulnerable groups. If there’s ever a topic to take extra care over, this is it. Whether or not the article’s authors declared this potential CoI to STM, Drisko is quite open about it elsewhere – her position as Chairman of ANH-USA is noted on the organisation’s website, so it doesn’t exactly take a courageous feat of investigative journalism to find out about this role. Despite a lot of media coverage of the article (Google News lists more than 300 pieces) none of the journalists writing about this topic appears to have noticed the potential CoI.

It is important for potential CoIs to be declared, so that readers can keep them in mind when assessing published work. Even if STM now makes some minor changes to the article, the damage has already been done by the media hype around this article’s launch: vitamin C has been widely publicised as a useful cancer treatment (although the Ma et al. article did not find any statistically significant difference in survival between patients treated with vitamin C and those receiving standard treatment). This STM article and the media coverage that accompanied it will be extremely useful to those campaigning for – and selling – the type of ‘integrative medicine’ that ANH-USA promotes.

* The publicity around the article often overstated its implications for cancer treatment in humans: NHS choices has done a nice job of summarising some limitations of the research and problems with this publicity.

** I learnt about Drisko’s role in ANH-USA through reading David Gorski’s critique of the article

*** Oddly, though, STM seem to view some financial details of this potential CoI – that it was non-financial – as not confidential: at least, they shared this information with me.

Postscript: my own potential conflicts of interest

Given the topic of this post, it seems reasonable to be open about my own potential CoIs. I have a general statement of interests here. Specific to this topic, I should also note that I have been involved in a campaign for more open declarations of UK doctors’ interests (this has been unpaid, although I have applied for funding for some related work). I have also done some voluntary work for one of the UK’s cancer charities. In terms of my personal views, I strongly disagree with most of the positions taken by ANH-USA (but would also defend the right of academics to engage in campaigning work, and have been involved in this type of work myself).